A regular JD would probably dominate the EBJD. Most EBJD's are not as aggressive. Never know, it all depends on each fishes tempermant.
For maximum potential out of the EBJD; house it alone as the only cichlid in the 50g. Use giant danios or silver dollars in with it as dithers.
Also an EBJD would not be a fish I would recommend to a person new in the hobby. They can be very prone to internal parasites and are on the expensive side if you make some mistakes. This is just my opinion, you may do just fine with it. But a couple of years of fishkeeping under your belt does give you more experience in dealing with these types of things.